The Cell Culture/Adenovirus and Lentivirus Preparation Core functions as a "Service Core" in this PPG. The specific aims of this service core are to: 1. Grow and maintain cell lines to be used by multiple investigators. 2. Keep frozen stocks of cells and retrieve cells from liquid N2 as requested by Core users. 3. Prepare media, seed, maintain and manipulate cells according to experimental protocols as requested by Core users. 4. Keep computerized list of all cells maintained by the Core. 5. Assign costs to PPG investigators for use of Core resources (provisions of cells. Adenovirus and Lentivirus preparations, etc) to be charged to Core A. 6. Provide small amounts of cultured cells to other investigators both within and outside of Hopkins for pilot experiments (charge-back to be used). 7. Provide cells/reagents (antibodies and cDNAs) of PPG investigators to scientists around Hopkins and outside Hopkins. 8. Train investigators in using epithelial cells in nature;train/advise personnel of PPG investigators concerning use of the Core facility. 9. Provide Adenovirus and Lentivirus construction, growth, purification and titering on basis of pay-for-service to PPG investigators. RELEVANCE (See instructions):